Advancement in high-density mounting technologies has been accompanied by the miniaturization, weight reduction, and increasingly high performance of electronic apparatuses in recent years, whereby packaging of electronic component devices has been changed from conventional pin insertion to surface mounting. In order to increase mounting density and reduce mounting height, surface-mounted ICs, LSIs, and the like are enclosed in thin and small packages. The area of elements occupied in packages has increased, whereas the thickness of the packages has become extremely thinner. Additionally, those packaging use a mounting method different from that in conventional pin insertion packaging. Specifically, when mounting an electronic component device on a wiring board, conventional pin insertion packaging has performed soldering from a back side of the wiring board after inserting pins in the wiring board so that the package is not directly exposed to high temperature. However, in surface-mounting packaging, the entire electronic component device is treated in a solder bath, a reflow apparatus and the like, and thus the package is directly exposed to a soldering temperature (reflow temperature). As a result, when the package has absorbed moisture, the absorbed moisture rapidly swells during soldering and then a generated vapor pressure acts as peeling-off stress, causing peeling off between an insert such as a lead frame and a sealing material. This will lead to the occurrence of package cracks and the deterioration of electric characteristics. Accordingly, development of a sealing material excellent in solder heat resistance (reflow resistance) has been desired.
In order to meet the requirements, various investigations have been made thus far on epoxy resin as a main material. However, mere improvement in epoxy resin has caused reduction of heat resistance due to reduced hygroscopicity, curability reduction due to improved adhesiveness, and the like, so that it has been difficult to achieve balance between physical properties. Thus, under the above circumstances, various epoxy resin modifiers are under investigation. As one example among them, silane coupling agents have been examined by focusing on improvement in adhesiveness with an insert such as an element lead frame. Specifically, there are an epoxy group-containing silane coupling agent or an amino group-containing silane coupling agent (for example, see Japanese Patent Application Laid-Open (JP-A) No. H11-147939) and a sulfur atom-containing silane coupling agent for further adhesiveness improvement (for example, see JP-A No. 2000-103940).